Base-exchange material and process for the production thereof



Patented Sept. 18, 1934 UNITED STATES BASE-EXCHANGE MATERIAL. AND PROCESS FOR THE PRODUCTION THEREOF Carl Christian Leopold Gether Budde, Copenhagen, Denmark No Drawing. Application January 5, 1931, Serial 8 Claims.

Base-exchanging substances as they occur in nature are for the most part unable to oiier resistance to water, and are therefore unsuitable as base-exchangers. In order to improve I their properties, the substances are subjected to burning, whereby the gels present lose the greater part of their water content. It is true that the gels become to a certain extent rehydrated owing to the action of electrolyte-containing-water. This re-hydration is a condition for the attainment of the greatest possible baseexchanging efficiency. Meanwhile, if the burning is suitably adjusted, the re-hydration does not reach a point where the substances thereby lose their solid structure.

Burning is, however, irrational, in as much as the substances thereby permanently lose in baseexchanging capacity. Thus, a base-exchanging clay which in nature can take up morethan 2% of CaO by means of base-exchange, loses more than half its base-exchanging capacity if it be burnt sufiiciently to ensure its subsequent non-suspension in water. Burning is, moreover, difiicult, as the measure of burning has to be extremely carefullly performed. Slight deviations to the one side or the other of the exact amount of burning to be observed are attended .with fatal results. This also applies to a certain extent to artificially prepared base-exchang- 30 ers. I

These shortcomings are avoided by means of this invention. According to the invention, natural or artificial base-exchangers are completely or in part stabilized by means of a binding material. In the stabilized product the binding material closely surrounds the particles of the baseexchanger, thereby preventing its dissolving or suspending in water.

In employing the invention with such arti- 40, ficial base-exchangers the binding material may be added to the one or the other of the soluble components before mixing, to produce the baseexchanger. It may be added at any point during manufacture.

The binding material to be used must, as it occurs in the finished stabilized base-exchanger, be in the possession of the following properties: (1) Insolubility, as far as possible, in water; (2) insensibility to acids, alkalis and other sub stances which might be present in the water; (3) permeability to water and the ions under consideration; and (4) sufiicient efiiciency, so that only a comparatively small quantity is needed for stabilization.

Certain organic substances having a high mo- In Denmark January 7, 1930 lecular weight, especially hydrates of cellulose, have proved specially suitable to meet these requirem'ents.

One mode of performing the invention consists, in the first place, of converting the cellulose into xanthate according to the well-known viscoseprocess. In this case, the base-exchanging substances or, 'where artificial base-exchanging substances are employed, one or several components thereof, may as occasion demands be mixed with 5 the xanthate solution, and the massleft to co-' agulate, or the coagulation may be brought about in a known manner by means of heat or precipitants. i l

The salts, etc. so formed are then washed out 7 with water, preferably soft water, in order to avoid clogging the pores of the mass. There remains the base-exchanging substance, permeated with hydrate of cellulose; The mass may be dried at ordinary temperaturesor by means of heat before or after washing. Moreover, the mass can be reduced, before orafter washing and'drying, to particles, of a mesh suitable for the purpose for which the base-exchanger is to be employed.

Another method ofperforming the invention is to convert the cellulose to xanthateand thereafter in a known manner to hydrate of cellulose, which is mixed before or after washing with the base-exchanging substance. Drying and/or crushing the finished mass may be carried out as above described. r

A third method consists in the direct conversion of the cellulose to the hydrate by vigor ous mechanical treatment with water, thereafter addingthis to the base-exchanging substance or, in the case of artificial base-exchanging substances, one or more of its component parts; This addition may take place atany point of the hydrating process. In this method with natural or finished base-exchanging products washing is unnecessary; drying and/or crushing of the finished mass may be performed as above described.

One of the reasons for cellulose being especially suitable as a binding material and protective medium is its powers of resistance to chemical action. Furthermore, it is extraordinarily effective. For example, in the case of base-exchanging clay an efiective binding was obtained with a quantity of cellulose not exceeding 10% of the weight ofthe clay. However, any proportion of binding material to the base-exchanging substance falls within the scope of this invent n. I 11,0

Of other binding materials suitable for the performance of the invention, albeit to a somewhat less degree, may be mentioned for example: casein, glue or gelatine and similar substances such as certain resins and bitumen. The meth- 0d of stabilization is in all these casesthe same, the base-exchanger or, in the case of artificial base-exchangers, one or more of their component parts, being mixed with the binding material in, for example, soluble or suspended form or in the form of a gel, whereupon the binding material, if soluble in water, is rendered insoluble in a known manner, and the mixture, if necessary, freed by washing from its water soluble components and reduced to grains of suitable size.

Example 1 The mixture for stabilization consists of a baseexchanging clay, which in the natural state is capable of exchanging 1.5% CaO and the analysis of which is as follows:

Per cent Loss by ignition 8.11 SiOz 65.75 F6203 5. 43 A1203 16.19 02.0 1.48 MgO 0.81 Alkali (difference) 2.24

10 kg. of this clay is suspendedin 10 kg. of water.

" Example 2 :-,The substancepfor stabilization consists of a base-exchanging clay, capable in the natural state of exchanging 1.0% 0210. Its analysis is:

' Per cent Loss by ignition (org. and chem. comb.

H2O) 17.00 A12 s 10.60 Iron. oxide (calculated as F6203) 5.10 eac 2.60 Mgo 0.76 NazO' 2.60 K20 1. 44 B20 8.

Chlorine and sulphate residue (difference) 2. 20

This clay 'is-crushed and sieved to a mesh 1640 (American normal sieve), whereupon 140 gr. is moistened with a solution of 3 gr. of casein and 0.5 gr. of calcined soda ashin 150 com. of water. It is then dried at 4050 C. It is then moistened with a solution of 20 com. formalin (40%) in 150 com. of water. It is again dried at a temperature of 40-50 C., whereupon the clay thus treated is allowed to stand for some hours at 80100 C.

In both cases the resulting product is completely stable, and undergoes no alteration, even when exposed to runningwater for several months, neither is it altered by frequent retion of ammonia. condensed, for example, by exposing the mix- 700 g. cellulose are converted ,to xanthate acgenerations. Its exchanging capacity remains likewise unaltered.

Example 3 300 gr. of crushed clay is impregnated with fluid phenol resin, prepared, for example, from mixture of 22 com. of raw-phenol, 22 ccm. of formalin (40%), and 15% concentrated solu- The phenol resin is then ture for 4 hours to a temperature of 150 C.

Y i r Example 4 Clay is intimately mixed with bakelite A 510%) in a roller mill, for example, the mixture pressed warm, and if necessary exposed to a further condensation process, as already described. The "hardmass is then crushed and sieved v Example 5 Example 6 Granulated clay is covered with tar and ex posed for an hour, for instance, to a temperature of .110? C. The excess of tar is. then removed centrifugally or by some similar process.-

' Example 7 V a gr. granulated clay is moistened with'a solutionoi 10 gr. of sugar in 50 com. of water. The sugar is then carbonized, the mixture being,

forinstance, exposed for two hours to a -temperature of 300 C. Y

7 Example 8 g l 100 gr. of finely ground clay is knea'dedto-Y gether with a solution of 10 gr. 'of sugar in 75 com. of water, the mass is then dried, crushed,

andsieved. The sugar ishereupon carbonized, as already described.

Example 9 The hydroxides of aluminum and iron are precipitated by neutralizing a solution of, for instance, 50 gr. aluminum sulphate and 50 gr. offerric chloride in 1000 ccm. of water. The hydroxides are then removed from the liquid by filtering, centrifuging, or the like, and kneaded together with 200 gr. of ground clay. The mass is then dried, crushed, and sieved. It is of great importance that in thisprocess the material is not subjected to burning but only dried, burning being to a certainextent detrimental to the base-exchanging capacity of the artificially produced base-exchangingv substance.

Example 10 A base exchanging material, e.g. is subjected to a heat treatment in a suitable furnace with fumes 'of a volatile compound preferably together with air or steam or both. The base exchanging material may be in the form of grains of a size suitable for its employment to base exchanging. A quantity of the volatile alkali compound, e.g. sodium chloride is placed in the hottest part of the furnace and the fumes formed by this compound may be passed over or through the base-exchanging material, placed in another part'of the furnace. The temperature of the base exchanging material during the treatment may preferably be 650-700" C. The alkali containing fumes will then enter into reaction with the surface parts of the grains of base exchanging material and possibly penetrate into said grains to act upon the material in the inner part of the grains forming with the silicates a fusible substance, which will act as a binding material. The reaction may be measured by measuring the amount of hydrogen chloride contained in the air or fumes issuing from the furnace. Only a slight amount of the silicates of the base exchanging material should be converted into the fusible alkali compound. The exact amount depends upon the raw material and the desired product. By variation of the amount of alkali which the raw material is permitted to take up the ratio of the base exchanging capacity to the hardness or resistibility of the material can be changed and said ratio can be made substantially more favorable than in case of burning the base exchanging material in the known way. This is due to the much shorter time required at equal temperature to bind the particles of the material together by this process than required for converting clay itself into a body of sufiicient resistancy as in the known processes of stabilizing baseexchanging clay by burning. In the present process most of the clay in the interior parts of the grains will remain substantially unconverted during the treatment with alkali and does not even decrease in base-exchanging capacity to any substantial extent. a The amount of reaction is always so slight that the base exchanging material when treated will not show any visible glaze as by the known salt glazing of pottery.

In many cases pressure may also be employed subsequently, as mentioned in Examples 4 and 6, in order to increase the solidity of the final product.

I claim:

1. A process for the stabilization of baseexchanging substances comprising the step of impregnating a base-exchanging substance with a bituminous material.

2. A process for the stabilization of baseexchanging substances, comprising the steps of mixing a base-exchanger with hydrate of cellulose in a moist state and drying the mixture.

3. A process for stabilizing base-exchangers, comprising the steps of converting cellulose into xanthate, mixing the cellulose xanthate with a base-exchanging substance and subjecting the mixture to a treatment which effects the conver sion of the xanthate into hydrate of cellulose.

4. A process for the stabilization of base-exchangers, comprising the steps of mixing a baseexchanger with casein and subjecting the mixture to a treatment with formaldehyde.

5. A process for the stabilizing of base-exchangers, comprising the steps of mixing the base-exchanger with a resinous substance and treating the mixture so as to make the resinous substance hard and resistant to water.

6. A granular base-exchanging substance the particles of which are surrounded and permeated with an organic binding material.

'I. A process for the production of a granular base-exchanging substance comprising the steps of dissolving an'organic binding material in hydrosol, precipitating a hydrogel, eliminating water from the gel and granulating the solid gel. 105

8. A process for the productionof granular base-exchanging substances, comprising the steps of mixing a binding material with one of the components from which an artificial base-exchanger can be prepared, bringing the mixture together with the other component of the base-exchanger to throw down the gel-containing a proportion of the binding material, separating, said gel eliminating water therefrom and grinding and hardening the binding material.

CARL CHRISTIAN LEOPOLD GETHER BUDDE 

